Work vehicles include a variety of types, such as construction machines, cargo handling machines, agricultural machines and the like. As for a cab 110 that is provided to such work vehicles, in the case of a hydraulic shovel 100 from among, for example, construction machines, as shown in FIG. 14, an upper structure 103 is installed so as to be freely rotatable via a rotary mechanism 102 on top of a lower traveling body 101, and a work machine 104 having a boom 105 that is provided so as to be able to move upward and downward, an arm 106 which is provided to the end of this boom 105 so as to be able to turn and move upward and downward, and an attachment 107, such as a bucket, that is provided to the end of this arm 106 so as to be able to move upward and downward; a power source, such as an engine 108; and cab 110 are mounted on the above described upper structure 103.
The above described cab 110 is generally formed so as to be in box form where a front window is provided on the front surface, a window that is as large as possible is provided on the rear, a window is also provided in the upper half of the side on which the above described work machine 104 is installed, and a door 111 is provided on the opposite side (left side of the vehicle) so that the operator can enter into or exit from cab 110 by opening and closing this door 111.
In cab 110 that is configured in this manner, electronic parts, such as switches that are required for operation, display apparatuses and air vents for an air conditioner (hereinafter referred to as air conditioning system) are provided, in order to increase working efficiency and make the working environment comfortable. These parts and apparatuses are placed along the wall portions so as to secure space and increase working efficiency. In addition, it is most desired for cab 110 of a work vehicle of this type, where operation is carried out while looking out through the front, to have a wide front view for operation through the front window. Therefore, cab 110 is designed in such a manner that the width of the front pillars that are located on both sides of the front in this structure is made as narrow as possible so as to reduce visual nuisances at the time of operation. Meanwhile, operation may be carried out in hydraulic shovel 110 in a state where the vehicle sits tilted on inclined ground, for example, when operation is carried out on a construction site having poor foothold, and in some cases, there is a risk that the vehicle may topple. Therefore, attempts are being made to toughen the structure of the frame of cab 110, so as to protect the operator inside cab 110, even in the case where the vehicle topples and the impact of toppling works on cab 110.
Meanwhile, improvement to the interior of the cab, in terms of creating a large space and enhancing comfort in order to increase workability and improve the working environment at the time of operation, as described above, and at the same time, making the space more comfortable by, for example, reducing noise, is a point that has been attracting attention. In Japanese Unexamined Patent Publication H9 (1997)-105150, a configuration where divided units are incorporated in a cosmetic cover, in such a manner that ducts for air conditioning are mounted in an interior portion, and electrical and mechanical functional parts are mounted so as to be located on side walls, and this cosmetic cover is made to make elastic contact with the sides of the cab is proposed.
In addition, Japanese Unexamined Patent Publication 2002-205528 discloses a technology for forming an installment panel that is installed within the cab of a vehicle such as a passenger car of the outer layer made of polyurethane foam and a foundation body panel made of hard polyurethane foam, so that a duct wall portion is integrally formed on the rear surface of the foundation body panel.
However, various types of functional parts are provided inside, making the shape on the surface of the structure different, depending on the portion, and therefore, the cosmetic cover for covering these parts on one inner side of the cab cannot be integrated in accordance with the interior technology for a cab that is disclosed in the above described Japanese Unexamined Patent Publication H9 (1997)-105150, and thus, a number of pieces that are formed in accordance with the portions are combined, where the end portion is treated using a rubber seal for attaching a window pane to the outer board in the configuration. Though this configuration is rational at a first glance, the task of assembly is complicated, and a problem arises, where the number of steps in the assembly is great and working efficiency is poor.
In addition, though an increase in the sound absorbing effects by using an installment panel made of polyurethane foam, which absorbs sound when the air conditioning unit that is installed inside operates, is expected in accordance with the prior art that is disclosed in Japanese Unexamined Patent Publication 2002-205528, a problem arises, where the effect of reducing noise from the outside of the cab of the work vehicle, which is greater in volume than the sound when the air conditioning unit operates, cannot be expected.
The present invention is provided in order to solve the above described problems, and an object thereof is to provide an interior member for the cab of a work vehicle, where ease of assembly of the interior member is increased and noise from the outside of the cab can be reduced, a method for forming the same, as well as a wall member.